George johnston



(No Model.)

JOHNSTON. ORE CRUSHING MACHINERY.

No. 559,779. I Patented May 5, 1896.

H 12-. /////////IIII!! wmvessss: V mum/r0)? 6M. 8. 00M). v 7*, QZZM% W% ATTORNEY.

' ANDREW BGRAHAMMOTOLUHQWASKINGTGNJC UNITED STATES PATENT Prion,

GEORGE J OIINSTON, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO THE RISDON IRON AND LOCOMOTIVE IVOR-KS, OF SAME PLACE.

ORE-CRUSHING MACHINERY.

SPECIFICATION forming part Of Letters Patent No. 559,779, dated May 5, 1896. Application filed September 24,1895. $erial No. 563,519. (No model.)

To aid whom it may concern.-

Be it known that I, GEORGE JOHNSTON, a citizen of the United States, residing in the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Ore-Crushing Machinery; and I hereby declare the following specification and the drawings therewith tov be a complete description of my improvement.

My invention relates to that class of ore crushing machines wherein the crushing is done in a cylindrical and flaring vessel or pan by means of rollers or otherwise, and to I 5 an adaptation of the escape-screens to the varying height of the surfaces between which the ore is crushed, and to preserving the screens from destructive wear by abrasion of the uncrushed ore.

My improvement consists in flexible plates that can be bent around to fit the contour of the cylindrical flaring pan placed inside the perforated screens and adjustable up or down thereon, as may be required, the height of the die or dialing, and in means to adjust and fasten such guard-plates in a proper position.

The main object of my invention is to protect the screens, which are fragile and expensivc, from the unpulverized ore that is by action of the crushing-rollers and dies shoved out laterally against the screens in a plane corresponding to the top of the dies. There is also the object necessary in some cases of regulating the height and area of the discharge-surface with respect to the operation of the machine.

Referring to the drawings, Figure 1 is a side elevation of an ore-crushin g machine provided with my improvements. Fig. 2 is an enlarged section on the line :0 a; in Fig. 1, showing particularly the method of applying my improved guard-plates. Fig. 3 is a fiat view of one of my improved guard-plates removed from the machine.

Like letters of reference indicate correspending parts throughout.

The main vessel or pan A is cast with a base-flangeB, a oollecting-trough O, terminat- 0 ing in a spout D, and a flange E around the top, to which is fastened a cylindrical case F,

inclosing the crushing mechanism of the machine and provided with a feed-spout D The crushing-rollers I, two or more in numher, are driven by a vertical shaft G, and this 5 5 by means of gear-wheels II II in the usual manner.

The dierin J is preferably made of steel and rests in a groove around the interior of the pan A, as shown in the section Fig. 2. These dies J when first prepared are nearly their width in depth, as seen in Fig. 2; but in use they are rapidly worn down by abrasive action of the ore, changing the crushing plane from the plane m down to n, so the relation to the bottom of the discharge-screens L is altered to that extent. In the plane in the broken uncrushed ore is shoved laterally by the rollers I, and if not interrupted impinges against the screens L, cutting or destroying them in this plane. To avoid this, I provide guard-plates U, made of thin metal, that can be laid on the inside of the screens L and temporarily fastened thereto in the required position. Then the screen L and its 7 5 plate M are bent around to fit against the curved and flaring sides of the pan A, and fastened by the frames N and keys 0 in the usual manner.

-When the die-ring J is worn down a suffi- 8o cient distance to permit further exposure of the screens L, the frames N are removed, the screens L and guard-plates M. taken out, and the latter fixed at a lower position, so following when required until the die-ring J is worn 8 5 down to the plane a.

I am aware that it is common in the case of stamp-batteries to adjust the screens upward and downward to suit the position of the dies; but such adjustment cannot be employed in the class of machines to which my invention applies and which have hitherto been, so far as I know, operated without such provision to protect the screens.

Having thus explained the nature and ch- 5 ject-s of my invention, also the manner of constructing and applying the same, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination with the pan and die of an ore-crushing machine formed with screenopenings, of the screens covering said openand the adjustable plates, clamped and held by the screen-frames.

3. The combination with the pan and die of an ore-crushing machine formedwith screen.- openings, of the screens, the screen-frames,

the, inside guard-plate adjustable up 01* down, and they keyswhereby the pants are removably held in place.

In testimony whereof I have hereunto af- 5 fixed my signature in the presence of two witnesses.

GEORGE; JOHNSTON.

Vitnesses:

ALFRED. A. EN UIsT, WILsON D. BENT, Jr. 

